With the explosive growth of the Internet, file-sharing programs have evolved. One popular file sharing program is known as Napster, with a user base that has grown to between 10 and 20 million users in 1 year. This is one of the fastest growing products today. Currently, scores of music files can be found from Napster's database of current online users, and downloaded from another user's computer, in a data transfer scheme known as peer-to-peer file sharing. File-sharing is easily extended to all content, such as done with Scour.com.
In the Napster system, web site servers store a database of directories of the digital music libraries on the hard drives of thousands of registered users. The digital files of the songs themselves remain on the users' hard drives. If a user wants a particular song title, he logs onto the Napster web site and types in a search query for the title. Client software on the user's computer connects to the Napster server and receives a list of active users who have the requested file on their computer. In response to selecting a handle name, the client software opens a link between the user's computer and the computer of the selected user, and the client software executing on the two computers transfer the requested file.
Many new file-sharing systems are evolving in which the database is dynamic and not stored on a central server. One example of software with a dynamic database is known as Gnutella. Initially, when a user logs on to the Gnutella network, the user downloads client software from a Gnutella website. Next, the user types in the Internet address of an established Gnutella user (e.g., from a listing available at the web site). The client software then transmits a signal on the network that informs other computers in the Gnutella file sharing network of its network address and connection status. Once a link with the other computer is secure, the other computer informs other computers of the Gnutella network that it has encountered in previous sessions of the user's presence (e.g., address and connection status).
After this initial session, the client software stores the addresses of other computers that it has encountered in the Gnutella network. When the client software is loaded, it recalls these addresses and attempts to reconnect with the other computers located at these addresses in the Gnutella network. The Gnutella software enables users to exchange many types of files. It enables users to issue a search request for files containing a desired text string. In response, the Gnutella clients connected with the user's computer search their respective hard drives for files satisfying the query. The client on the user's computer receives the results (e.g., files and corresponding addresses) and displays a list of them. By clicking on a file item in the user interface, the user instructs the client software to transfer the selected file.
In another file sharing system known as Freenet, the identity of the person downloading and uploading the files can be kept secret. Alternatively, the files could be stored on a central server, but uploaded by users such that the central server does not know the origin or true content of the files.
Unfortunately, the file-sharing methodology also allows massive piracy of any content, such as text, music, video, software, and so on. However, due to the scalability and freedom of distribution with file-sharing, it provides a powerful tool to share information. As such, the is a need for technology that facilitates and enhances authorized file sharing while respecting copyrights.
A few examples of the benefits of file-sharing follow. A file sharing system allows unknown artists to obtain inexpensive and worldwide distribution of their creative works, such as songs, images, writings, etc. As files become more popular, they appear on more of the users' computers; thus, inherently providing scalability. In other words, there are more places from which to download the file and most likely several files exist in close proximity to the downloading computer, thus improving efficiency. In addition, anonymous file-sharing, like FreeNet, foster political debate in places around the world where such debate might trigger reprisals from the government.
Current attempts to curb unauthorized file sharing include enforcement of copyright laws and use of files with content bombs. The current legal enforcement efforts allege that uses of file sharing systems violate copyright laws. Content bombs involve placing files that appear to be the correct content, but contain alternative content or viruses. For example, a MP3 file can have the middle replaced with someone saying “do not copy songs” instead of the desired music. Neither of these solutions will help the Internet grow and improve the quality of life, worldwide.
Current copy management systems allow copying, but block rendering on equipment if the person does not have rights, where rendering only refers to reading a text file, seeing an image, watching a movie, listening to an audio file, smelling a smell file, or executing a software program. Although this can limit piracy within a file-sharing system, it does not improve the system for the user. This lack of improvement stems from the fact that current copy control systems are implemented on the user's computer at the time of importing into the secure system, rendering, or moving to a portable rendering device or media, as described in the Secure Digital Music Initiative's specifications version 1 (available at http://www.sdmi.org, and incorporated by reference). In other words, current copy control systems do not check rights at the time of copying or transfer between computers. For example, the user downloads the protected file, and then finds out that he/she cannot render the file (i.e. play the song). In addition, the user does not know if the file is the correct file or complete until after downloading and attempting to render the file. More specifically, the file is encrypted by a key related to an unique identifier within the user's computer; thus, after copying to a new computer, the file cannot be decrypted. In addition, watermarks can only be used after the file has been decrypted, or to screen open (i.e. decrypted) content for importation into the user's secure management system after the file has been copied to their computer.
Another approach would be to use a database lookup to determine whether the content is allowed to be shared. For example, music in the MP3 file format can be determined whether it can be shared by the ID3 song title tag. However, this solution does not scale. Specifically, every downloaded file needs to access and search this central database, and this database's access does not improve as the file becomes more popular. In addition, the approach can be bypassed by changing the file's title tag or filename, although this makes searching more difficult.
A desirable solution includes embedding data throughout the content in which the embedded data has any of the following roles. The embedded data can have an identifier that identifies the file as the content that the user desires. The embedded data can be analyzed in terms of continuity throughout the file to quickly demonstrate that the file is complete and not modified by undesirable content or viruses. An additional role is to identify the content as something that is allowed to be shared, or used to determine the level or type of sharing allowed, such as for subscription users only.
The embedded data may exist in the header or footer of the file, throughout the file as an out-of-band signal, such as within a frame header, or embedded in the content while being minimally perceived, most importantly without disturbing its function, also known as a watermark.
In the utilization of this embedded data, the computer from which the content to be downloaded (i.e. the uploading computer) can check to make sure the content is appropriate to be uploaded when the files (e.g., music files) on this computer are added to the central database and/or when the content is requested. Similarly, the downloading computer can also check that the requested content is appropriate before or during the downloading process. An appropriate file can be defined as any of the following: the content is allowed to be shared, i.e. it is not copyright material, the file is the correct content, and that the content is complete and does not contain any viruses.